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1-how is cell cycle controlled?

what stage of cell cycle?

2-What is the difference between a chromatid and sisterchromatids ?

3-What is the difference between sister chromatids and non-sister chromatids of homologous chromosomes ?

4- What is nondisjunction and what might result from it?

5-define apoptosis and explain why it may occur?


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Sixta Kovacek
Sixta KovacekLv2
28 Sep 2019

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Related questions

4. The following questions dealwith the organization of the genetic material within a cell. Makesimple sketches (or describe) to help you visualize the variousstructures as you answer these questions.

  • What is chromatin?
  • How is chromatin related to a chromosome?
  • The length of a single chromosome is several thousandtimes the diameter of the cell containing it. How is it possible tofit such large structures into a cell?
  • What are sister chromatids? What connectsthem?
  • Do all cells in your body have the same number ofchromosomes? Explain why.
  • What are homologous chromosomes?
  • What is the difference between a sister chromatid and achromosome?
  • Is the structure only called a chromosome when it is madeup of two sister chromatids? Explain.

5. List the phases of the cell cycle anddescribe the sequence of events that occurs during eachphase. Use the masteringbio website, chapter 12,activity 2 (The cell cycle), more important is activity 3 (Mitosisand cytokinesis animation). Greatreview!

-Complete the following sentences: metaphase of mitosis, prophase II of meiosis, crossing over, anaphase I of meiosis, variable, random fertilization, identical, random orientation, metaphase I of meiosis, prophase I of meiosis, metaphase II of meiosis, reduction division

Two processes that occur during meiosis produce genetically ____________ cells.

In a process called ____________ , paired homologous chromosomes align randomly at the cell equator. This occurs during this stage of cell division: ____________ .

In a process called ____________ , genetic material is exchanged between homologous chromosomes. This occurs during this stage of cell division: ____________ .

-Complete the following paragraph to describe nondisjunction and the resulting effects on chromosome number.

words: euploidy, primary nondisjunction, nomal, nondisjunction, secondary nondisjunction, homologous chromosomes, abnormal, trisomy, monosomy, sister chromatids, aneuploid

1.During meiosis I, ____________ separate and move towards opposite ends of the poles.

2.During meiosis II, ____________ separate and move towards opposite ends of the poles.

3.During meiosis I, if both members of a homologous pair go into the same daughter cell, ____________ is said to occur and no normal gametes are produced.

4.During meiosis II, if the sister chromatids fail to separate and both daughter chromosomes go into the same gamete, ____________ is said to occur. Half the gametes are aneuploid while the other half are euploid.

5.If an egg that contains 24 chromosomes instead of 23 chromosomes is fertilized by a normal sperm, ____________ is said to have occurred.

6.If an egg that contains 22 chromosomes instead of 23 chromosomes is fertilized by a normal sperm, ____________ is said to have occurred.

Which of the following best describes what happens next to the energy from a photon of light after it excites an electron in the pigment molecule of a plant?

a. The excited electron carries the energy to the primary electron acceptor in the reaction center complex

b. the energy is released as heat and the electron drops back down to its ground state

c. the energy is passed to the other electrons in the light-harvesting complex until it reaches the reaction center complex and reduces the primary electron acceptor

d. the energy is released as light and the electron drops back down to its ground state

e. the excited electron carries the energy to the reaction center complex and oxidizes the primary electron acceptor

2. chromosomes are replicated in the _______ of a cell and sister chromatids are separated in the ____

a. nucleus; cytosol

b. nuclear envelope; nucleus

c. nuclear lamina, nucleus

d. cytosol; cytosol

e. centriole; nucleus

3.which of the following accurately describes a difference between sister chromatids and a chromosome?

a. a pair of sister chromatids contain 2 double-stranded molecules of DNA and a chromosome has 4 double-stranded molecules of DNA

b. each sister chromatid has a single strand of DNA and chromosomes have 2

c. sister chromatids have centromeres and a chromosome does not

d. a pair of sister chromatids contain identical genes, and a chromosome does not

e. sister chromatids are produced during M phase and chromosomes are always present in the cell cycle

4. all of the following take place during mitosis except..

a. DNA is proofread for replication errors

b. chromosomes are replicated

c. the mitotic spindle is formed

d. the nuclear envelope breaks down

e. sister chromatids are separated

f. A and B only

g. B and C only

h. C and D only

i. D and E only

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